Method of working expansion-engines.



PATENTED APR. 28, 1908.

E. HILDEBRAND. METHOD OF WORKING EXPANSION ENGINES APPLICATION FILED FEB. 19, 1907.

FRITZ HILDEBRAND, OF DEUTSOH WILMEBSDORF, GERMANY.

METHOD OF WORKING EXPANSION-ENGINES.

Specification of Letters Patent.

Patented April 2a, 1908.

Application filed February 19, 1907. Serial No. 358,197.

To all whom it may concern:

Be it known that I, FRITZ HILDEBRAND, a subject of the German Emperor, residing at Deutsch Wilmersdorf, near Berlin, in the Kingdom of Prussia, Germany, have invented certain new and useful Improvements in Methods of Working Expansion-Engines, of which the following 1s a specification.

The subect of my invention is a method or process 0 working expansion engines by means of liquefied ases, and particular of liquid carbonic aci and liquid a1r, the liquefied gas, being for this purpose brought together with compressed air. I

After mingling of the hot compressed air with the vapors which arise from the liquefied gas, a high degree of expansionoccurs. On expansion of the mixture the exhaust temperature will not fall below zero thus causing ice to form in the engine, provided the proportions of the two agents employed into vapor.

aresuitably selected and their pressure, or the'temperature, before ,mixing taken into account. 1

The e ansive mixture may with advantage be a lowed to act directly upon the iston of the ex ansion engine, only so muc of the mixture eing roduced each time as is necessary for a wor ing stroke.

In carrying my new method into effect in ractice, the necessary compressed air may,

if desired, be generated in well-known manner by the expansion engine itself, atmos pheric air which enters into the working cylinder being compressed by the piston, whereupon, say at .the moment of eatest compression, the liquefied gas is admitted to the working cylinder where it is converted The expanding mixture drives the piston forward. The expansion engine may work either as a two or four stroke cycle engine. f

The accompanyin drawing by way of example shows one orm of engine (for instance working on the two stro e cycle) to which the invention has been applied, the

figure being a vertical section. m

At the first stroke the piston 0 draws atmospheric air into the. working cylinder 6 through the valve '11 and compresses it on the return stroke. About at the moment of reversal, that is of maximum compression of the air, the liquefied gas under considerable pressure flows from the reservoir 1) (constructed in the manner of a siphon bottle) and passes through the pipe 0 and positively controlled nozzle 01 into the cylinder e, where it is vaporized on contact with the hot compressed air and mingles with the latter. The mixture in a state of high tension expands and drives forward the piston until the latter exposes the exhaust port f.

On ascent of the piston a, its lower face will have drawn atmospheric air into the crank. chamber Z through the automatic valve 9, which air on descent of the piston is forced into the passage h. As long as the pressure in the cylinder 6 is higher than that in the passage h the automatic valve 2', remains closed. (ln opening of the exhaust port f and exit of the expansive mixture, the 7 conditions of pressure are reversed, and the under-pressure in the cylinder e, even although byemployment of a silencer it will be but small, is suflicient to permit atmospheric air to enter the cylinder, whereby the latter will be swept perfectly clean and charged anew. The iston a now-ascends again, on the one hand compressing the air which has {ust entered, and on the other hand with its ower face drawing fresh air into the chamber Z; while at the moment of its reversal liquefied gas enters through the ositively controlled nozzle (1 into the cylin or space e, and the rocedure is repeated.

The nozzle dis regiulable during running of the engine, in order y the supply to regulate the number of revolutions of t e latter. automatic valves g, i cannaturally also be positively actuated in well-known manner if circumstances render this desirable.

In the drawing, 7c is the connecting-rod, m the cam actuating the nozzle ear rod n, and r 1' the transmission gearing or the same. i

The provision of a siphon bottle I) would. @ppear practical only for stationary plants.

or vehicles and boats, where ordinary receptacles have to berelied on, it would be simplest to overturn the bottle, so that the gases forming above the liquid force the latter out.

It may, in some cases, prove advantageous to heat the atmospheric air prior to its en trance into the workin cylinder, firstly, in order to keep the latter 0t, if necessary, and secondly, to alter the compression of the air or the proportions of the mixture or its ex- The working cylinder. Or if fresh air is drawn in through the jacket, it is heated by the Walls of the working cylinder rendered hot by the heat of compression, whereby needless cooling of the cyllnderis prevented.

Having thus described my invention, I claim as new and, desire to secure by Letters Patent 1. The method of working an expansion en ine, consisting in supplying the working cy inder with liquefiedgas andlco'mpressed air, and allowing the mixture to expand, substantially as described,

2. The method of working an expansion engine, consisting in supplying atmospheric air to the working cylinder, and compressing it by means of the piston, and thereupon admitting liquefied gas into the said cylinder,

and allowing the mixture to expand, substantially as described. I

3. The method of working an expansion engine, consisting in supplying atmospheric air to the working cylinder and compressing it by means of the piston and at the moment of maximum compression admitting liquefied gas into the said cylinder, and allowing the mixture to expand, scribed.

In' testimony whereof I have hereunto signed my name in the presence of two subscribing Witnesses.

FRITZ. HILDEBRAND'.

substantially as de- 

